Crustacean venom offers potential breakthrough in neurology

The journal BMC Biology reports that toxins produced by the crustacean Xibalbanus tulumensis, which lives in submerged caves on the Yucatán Peninsula, may be used to treat neurological diseases.

Venom many animals produce, comprising toxins, is typically used for self-defence or hunting. These toxins disrupt various physiological processes, which makes them particularly interesting from a pharmacological perspective.

Until now, the most understood venoms were those of certain groups of animals, such as snakes, spiders, or scorpions. However, much less is known about toxins found in marine animals, creating significant opportunities for new discoveries.

Just a few years ago, venomous crustaceans belonging to the group Remipedia living in water-filled caves were discovered.

Dr. Björn von Reumont was the first, in 2014, to describe the ability of Remipedia to produce venom. He is continuing studies on this phenomenon along with an interdisciplinary team of researchers from Goethe University in Frankfurt. The team collaborates with the Fraunhofer Institute for Translational Medicine (ITMP) and research centres in Leuven, Cologne, Berlin, and Munich, among others.

As a result of the research, scientists characterised a group of toxins produced by the Remipede Xibalbanus tulumensis, which resembles a centipede. The name of this crustacean comes from "Xibalba," referring to the mythical underworld of the dead, whose entrances are said to be located in cave systems on the Mexican Yucatán Peninsula.

The mentioned animal injects venom into its prey through a special venom gland. The toxin's composition is exceptionally diverse, and the latest studies have revealed the presence of a new type of peptide, named by scientists as xibalbin.

Some of the xibalbins contain unique structural elements similar to those known from other venomous animals, including spiders. These peptides have a knot-like structure, making them resistant to enzymes, high temperatures, and extreme pH values.

Such knot-like structures often operate as neurotoxins, interacting with ion channels and paralysing the victim. Research has shown that numerous xibalbins, particularly Xib1, Xib2, and Xib13, can block potassium channels in mammalian cells.

This inhibition is greatly important when it comes to developing drugs ... range of neurological diseases, including epilepsy, explained Dr. Björn von Reumont.

Moreover, Xib1 and Xib13 can also block voltage-gated sodium channels, such as those found in nerve or heart muscle cells.

Research also revealed that in higher mammalian sensory neurons, these peptides can activate two key proteins — PKA-II and ERK1/2 kinases. These processes suggest that peptides play a role in the pain sensitisation mechanism, thus opening new perspectives in the treatment of pain conditions.

Finding suitable candidates and comprehensively characterizing their effects, thus laying the foundation for safe and effective drugs, is only possible today in a large interdisciplinary team, as in the case of our study, indicated von Reumont.

Researchers face many challenges. Their work is hampered by the fact that the habitat of the Remipedes is seriously threatened by the construction of the Tren Maya intercity railway, which cuts through the Yucatán Peninsula.

— The cenotes (natural limestone wells filled with water) are a highly sensitive ecosystem, emphasised von Reumont, who, as an experienced cave diver, personally collected Remipedes during an expedition to the Yucatán. — Our study highlights the importance of protecting biodiversity, not only for its ecological significance but also for potential substances that could be of crucial importance to us humans, he noted.